Abstract: A quantitative method for nuclear medicine heart image and an electronic device are provided. The method is adapted for multi-pinhole SPECT images or SPECT/CT images. The method includes a radionuclide physical decay correction, a scatter correction, a geometry distortion correction, a data truncation compensation, a tissue attenuation correction, an image space resolution recovery, a noise removal, a pixel value conversion, a myocardial blood flow quantitative calculation, an intra-scan patient movement correction and a blood flow condition evaluation. Accordingly, a quantitative SPECT reconstructed image of a heart is obtained, and an absolute quantization of the myocardial blood flow is calculated to measure the myocardial blood flow quantitatively according to the quantitative SPECT reconstructed image.

Abstract: The disclosure relates to a system and method for image reconstruction. The method may include the steps of: obtaining raw data corresponding to radiation rays within a volume, determining a radiation ray passing a plurality of voxels, grouping the voxels into a plurality of subsets such that at least some subset of voxels are sequentially loaded into a memory, and performing a calculation relating to the sequentially loaded voxels. The radiation ray may be determined based on the raw data. The calculation may be performed by a plurality of processing threads in a parallel hardware architecture. A processing thread may correspond to a subset of voxels.

Abstract: Methods and apparatus, including computer programs encoded on a computer storage medium, for image reconstruction are provided. According to an example of the methods, an image reconstruction may be performed to generate a first set of reconstructed data with a first set of projection data comprising a plurality of first projection data each corresponding to a respective projection angle of a plurality of projection angles. A second set of projection data comprising second projection data for each projection angle may be generated with the first set of reconstructed data. The first set of projection data may be corrected based on a shifting distance between the first projection data and the second projection data for each projection angle. Then, a second set of reconstructed data may be generated with the corrected first set of projection data, and a reconstructed image may be generated according to the second set of reconstructed data.

Abstract: An on-line energy coincidence method for an all-digital PET system, comprising: a detection module conducting information collection on a scintillation pulse, forming a single event data frame and sending it to an upper computer; the upper computer conducting two-bit position distribution statistics on an incident gamma photon event and conducting position spectrum partition; performing statistics on an energy distribution spectrum of each crystal bar, so as to acquire an energy correction value; the detection module uploading a crystal bar partition data table and an energy peak correction data table; starting information collection of on-line energy correction; when an event is coming, according to a two-dimensional coordinate thereof, from the crystal partition table, searching for a crystal bar number corresponding thereto, and searching for an energy correction value from the energy correction table; and sending data passing the energy coincidence to the upper computer.

Abstract: Systems and methods for driving a flexible medical instrument to a target in an anatomical space with robotic assistance are described herein. The flexible instrument may have a tracking sensor embedded therein. An associated robotic control system may be provided, which is configured to register the flexible instrument to an anatomical image using data from the tracking sensor and identify one or more movements suitable for navigating the instrument towards an identified target. In some embodiments, the robotic control system drives or assists in driving the flexible instrument to the target.

Abstract: A controller for detecting objects moving in a first direction in a computed tomography (CT) imaging system is provided. The controller is configured to detect objects by assembling a plurality of segments based on a plurality of CT imaging slices. In response to receiving a stop request, the controller is configured to detect objects by causing the CT imaging system to cease a flow of objects, discarding the one or more of the plurality of CT imaging slices associated with a first segment and a second segment of the plurality of segments, causing the CT imaging system to move the objects in a second direction for an interruption distance in which the second direction is opposite the first direction, causing the CT imaging system to move the objects in the first direction, and reassembling the first segment and the second segment.

Abstract: Embodiments are disclosed for systems for a vehicle. An example system for a vehicle includes a head-up display, a central unit having a circuit, connected to the head-up display, and a recording means for recording first image data of surroundings of the vehicle, wherein the circuit is configured to recognize an object in the surroundings based on the recorded first image data, wherein the head-up display is configured to project an image onto a windshield or onto a combiner of the vehicle, and wherein the circuit is configured to generate second image data for outputting the image and to send the image to the head-up display, to generate a virtual barrier in the second image data, and to position the virtual barrier within the image based on a determined position of the recognized object.

Abstract: An imaging system (300) includes a radiation source (308) that emits radiation that traverses in a direction of an examination region (306) during a scan and a detector array (316) located opposite the radiation source, across the examination region, which detects radiation traversing the examination region during the scan and produces a signal indicative thereof. A beamshaper (318), located between the radiation source and the examination region, defines a flux intensity profile of the radiation beam traversing the examination region. The beamshaper includes a plurality of x-ray attenuating elements(326), which attenuate x-rays incident thereon, interleaved with a plurality of material free regions, which pass x-ray unattenuated. A transmittance of the x-rays is greater nearer a center region of the beamshaper relative to ends regions of the beamshaper. A beamshaper mover (328) translates the beamshaper during at least one acquisition interval of the scan.

Abstract: Methods, systems, and computer-readable mediums are provided that determine the angular orientation of detectors and detector electronic assemblies (“DEAs”). In various embodiments, the orientation of detectors/DEAs (in the ring) is determined with respect to other detectors/DEAs in the ring, the orientation of the detectors/DEAs with respect to a patient bed, or the orientation of the detectors/DEAs with respect to Earth's gravitational field. In another embodiment, a nuclear medical imaging system has one or more detector units arranged around or that can be swept around a patient bed. Each of the detector units includes an angular orientation-sensing accelerometer. By determining angular orientation of the detector from signals outputted by the accelerometer, the circumferential position of the detector relative to the patient bed can be determined. That information is used in conjunction with information about detected events to construct an image of an organ or tissue mass of interest.

Abstract: Nuclear medicine (NM) imaging system includes a detector assembly coupled to a gantry. The NM imaging system also includes a positioning sub-system having a motion controller and a detector motor. The positioning sub-system also includes a proximity sensor device (PSD) coupled to a detector head of the detector assembly. The PSD is configured to be activated. In response to being activated, the PSD is configured to transmit an output signal to stop the detector motor from moving the detector head toward the object. The NM imaging system also includes a secondary circuit that, in response to the PSD being activated, is configured to determine whether the detector head has stopped moving toward the object and, if the detector head has not stopped moving toward the object, is configured to disable the detector motor.

Abstract: Motion correction is performed in time-of-flight (TOF) positron emission tomography (PET). Rather than applying motion correction to reconstructed images or as part of reconstruction, the motion correction is applied in the projection domain of the PET data. The TOF data from the PET scan is altered to account for the motion. The TOF data is altered prior to starting reconstruction. The motion in the patient or image domain is forward projected to provide motion in the projection domain of the TOF data. The projected motion of different phases is applied to the TOF data from different phases, respectively, to create a combined dataset of motion corrected TOF data representing the patient at a reference phase. The dataset is larger (e.g., similar size from projection data dimension point of view, but contains more counts per projection data unit or is more dense) than available at one phase of the physiological cycle and is then used in reconstruction.

Abstract: A robotic arm, movable in three rotational degrees of freedom has a base end and a distal end supporting SPECT imaging detectors. A patient support assembly is movable in a linear degree of freedom. A controller causes the robotic arm to move the SPECT imaging detectors, in three dimensions, around the patient's body to obtain SPECT images. The control causes the patient support assembly to move along the linear degree of freedom, maintaining alignment of the patient's body with the SPECT imaging detectors.

Abstract: A collimator for a SPECT system, the collimator being adapted for absorbing and collimating gamma rays emitted by a radiation source within a field of view the collimator, said collimator having an alignment direction for directing along a longitudinal axis of a measuring cavity of the SPECT system and said collimator comprising at least one collimator body of radiation absorbing material, the collimator body comprising a plurality of apertures being formed in the collimator body, the plurality of apertures being arranged in a plurality of groups separated from each other in said alignment direction. The apertures of each group are oriented such as to define at least one projection view along a corresponding at least one projection direction. The plurality of said projection directions corresponding to each and every of said plurality of groups cover an angular range sufficiently large for sufficient image information for artifact-free reconstruction.

Abstract: A calibration rig and calibration method for an imaging system includes a base and a holder extending from the base, the holder including a fixture configured to hold a radioactive source material in a two-dimensional geometric configuration and a radioactive source material disposed in the fixture.

Abstract: Radioimaging methods, devices and radiopharmaceuticals therefor.

Abstract: Noise of a CT image is reduced with good accuracy by using noise information obtained from the CT image. An X-ray CT apparatus comprises a successive approximate reconstruction part that reconstructs a CT image for a reconstruction area of an imaging object from measured projection data obtained by an X-ray detection part of the X-ray CT apparatus, and successively corrects the CT image so that calculated projection data obtained by forward projection of the CT image performed by calculation and the measured projection data detected by the X-ray detection part become equal to each other. The successive approximate reconstruction part comprises a noise measurement part that calculates noise intensity in the CT image at least for a predetermined region of interest, and successively corrects the CT image of the region of interest by using the calculated noise intensity.

Abstract: Methods and systems are provided for correcting positional errors in an image arising from gaps in a detector assembly. In one embodiment, a method comprises generating a sinogram based on a plurality of photon coincidence events, selectively inserting one or more pseudo-slices into the sinogram, and generating an image based on the sinogram including the one or more pseudo-slices. In this way, positional errors may be reduced without modifying an image reconstruction algorithm to include a full detector geometry or modifying the detector geometry itself.

Abstract: A customizable and upgradeable imaging system is provided. Imaging detector columns are installed in a gantry to receive imaging information about a subject. Imaging detector columns can extend and retract radially as well as be rotated orbitally around the gantry. The gantry can be partially populated with detector columns and the detector columns can be partially populated with detector elements.

Abstract: Methods and systems are provided for medical imaging systems. In one embodiment, a method comprises estimating an external scatter contamination in emission data based on an estimated emission activity originating from anatomies outside a field-of-view (FOV) of a scanner, the anatomies identified based on an image segmentation analysis performed on an image generated in the imaging system, the image generated prior to acquiring the emission data. In this way, a scatter correction applied to the emission data may include both scatter originating within the FOV and outside the FOV, and hence may be more accurate.

Abstract: Disclosed herein is a partially movable radiation tomography apparatus capable of superimposing an anatomical image and a functional image without causing misalignment. The apparatus of the disclosure includes a device associated with a CT gantry having a top board, and a device associated with a PET gantry. The latter device is attachable and removable to/from the former device. This apparatus can reduce positional misalignment between the images captured by these devices. The present disclosure involves making a correction for positioning the subject images captured by the devices associated with the respective gantries with respect to each other based on a calibration image on which markers m attached to those gantries are shot. Such a configuration allows for positioning the subject images with possible misalignment between the gantries taken into account, and eventually reducing positional misalignment between the subject images captured by the devices associated with the respective gantries.

Abstract: A PET detector and method thereof are provided. The PET detector may include: a crystal array including a plurality of crystal elements arranged in an array and light-splitting structures set on surfaces of the plurality of crystal elements, the light-splitting structures jointly define a light output surface of the crystal array; a semiconductor sensor array, which is set in opposite to the light output surface of the crystal array and is suitable to receive photons from the light output surface, the semiconductor sensor array comprises a plurality of semiconductor sensors arranged in an array.

Abstract: Methods and systems according to the present disclosure improve upon known biometric security systems by not permanently storing (e.g., for later comparison as in known systems) the actual image of the biometric characteristic. Instead, an image of a biometric identifier (e.g., retina, fingerprint, etc.) may be used to form a key which may be used to secure and provide access to data. The key may be formed, in embodiments, using a neural network and/or a random input (e.g., a vector of random characters), for example. The image of the biometric identifier may be discarded, and thus may not be vulnerable to theft. In an embodiment, the key may be used in a key-based encryption system.

Abstract: Focusing on a gamma ray detection phenomenon (event) in which a gamma ray from a gamma ray source is Compton scattered at a first-stage detector, the gamma ray is photoelectrically absorbed at a second-stage detector, the spatial distribution of the gamma ray source is imaged within a predetermined image space on the basis of measurement data for the interaction of the detectors and gamma rays. At this time, a probability parameter (vij) indicating the probability that Compton-scattered gamma ray arrived from within the image space and a detection sensitivity parameter (sij) indicating gamma ray detection sensitivity are set for each event and each pixel on the basis of the measurement data for each event, and these parameters are used to determine the pixel values (?j) for each pixel.

Abstract: To improve the scanning effect, a scanning method is provided, which comprises the steps of performing at least one of an nCT scan and a CTA scan on an object so as to obtain a set of images; detecting characteristics of a region of interest based on the set of images; and performing a CTP scan on the region of interest by adopting the characteristics to obtain a CTP image. By deriving the characteristics of the region of interest, e.g. a lesion or an area covering the lesion, before performing the CTP scan, and by adapting the subsequent CTP scan based on the characteristics of the region of interest, the drawback introduced by a limited scan area of the CTP scanner is mitigated, or even overcome.

Abstract: Methods and systems are provided for multi-window imaging. In one embodiment, a method comprises segmenting an image reconstructed from acquired projection data into segments, converting pixel values based on a mapping for each segment to generate converted segments, and outputting, to a display device, a composite image comprising a combination of the converted segments. The composite image includes a border delineating the converted segments. In this way, multiple windows collectively covering a large dynamic range may be combined into a single image.

Abstract: A PET detection structure with application adaptability includes: at least two detector blocks and a detection ring for disposing the detector blocks. The at least two detector blocks are placed on the detection ring and surround a detected object in a manner of encirclement. The performance of each detector block includes inherent spatial resolution, time behavior, energy resolution, detection efficiency and maximum counting rate. The performance of the detector blocks are divided into a plurality of performance levels, and the performance level of one performance of at least one detector block of the at least two detector blocks is higher than the performance rate of the same performance of the other detector blocks.

Abstract: A PET detector and method thereof are provided. The PET detector may include: a crystal array including a plurality of crystal elements arranged in an array and light-splitting structures set on surfaces of the plurality of crystal elements, the light-splitting structures jointly define a light output surface of the crystal array; a semiconductor sensor array, which is set in opposite to the light output surface of the crystal array and is suitable to receive photons from the light output surface, the semiconductor sensor array comprises a plurality of semiconductor sensors arranged in an array.

Abstract: An imaging system includes plural modular imaging detectors and a readout electronics unit. Each modular imaging detector includes pixels configured to collect imaging data, a substrate on which the pixels are disposed, and a mechanical interconnection feature. The mechanical interconnection feature is configured to cooperate with a corresponding mechanical interconnection feature of at least one other of the modular imaging detectors to directly join the modular imaging detector to the at least one other of the modular imaging detectors. The readout electronics unit is configured to be operably coupled to the modular imaging detectors and to receive signals corresponding to the imaging data from the modular imaging detectors.

Abstract: An electronic apparatus having at least two camera devices and a processing device. The processing device: determines a first length between an object positioned at a first time and a surface formed by the two camera devices, determines a second length between the object positioned at a second time and the surface, determines a third length between the object positioned at a third time and the surface, and determines a depth in a virtual space corresponding to the object positioned at the third time according to the first length, the second length, and the third length. In operation, the third time is later than the first time and the second time, and the third length is longer than the first length and shorter than the second length.

Abstract: An apparatus and method for measuring three-dimensional radiation dose distributions with high spatial and temporal resolution using a large-volume scintillator. The scintillator converts the radiation dose distribution into a visible light distribution. The visible light is transported to one or more photo-detectors, which measure the light intensity. The light signals are processed to correct for optical artifacts, and the three-dimensional light distribution is reconstructed. The reconstructed light distribution is post-processed to convert light amplitudes to measured radiation doses. The high temporal resolution of the detector makes it possible to observe the evolution of a dynamic dose distribution as it changes over time. Integral dose distributions can be measured by summing the dose over time.

Abstract: A customizable and upgradable imaging system is provided. Imaging detector columns are installed in a gantry to receive imaging information about a subject. Imaging detector columns can extend and retract radially as well as be rotated orbitally around the gantry. The gantry can be partially populated with detector columns and the detector columns can be partially populated with detector elements.

Abstract: A C-arm mounting apparatus for an x-ray imaging device includes a C-arm, a C-arm holding unit, and at least one cage guide unit. The at least one cage guide unit is moveably arranged between the C-arm and the C-arm holding unit. The C-arm is moveably mounted on the C-arm holding unit. The at least one cage guide unit includes a plurality of rolling bodies and at least one rolling body cage. The small overlap between the C-arm and the C-arm holding unit may facilitate greater rotations about an isocenter. An x-ray imaging device includes a C-arm mounting apparatus.

Abstract: A method is disclosed for determining a position-dependent attenuation map of at least one surface coil of a combined magnetic resonance/PET apparatus. In an embodiment, the method includes acquiring magnetic resonance image data by way of the at least one surface coil during a magnetic resonance/PET examination of a patient; reconstructing the position of the at least one surface coil on the basis of the acquired magnetic resonance image data; and determining the position-dependent attenuation map of the at least one surface coil on the basis of the reconstructed position of the at least one surface coil. A magnetic resonance/PET apparatus and a computer program product, embodied to perform the method, are also disclosed.

Abstract: A volumetric imaging device for constructing a three dimensional image includes a source, and absorbing detector, and an image constructor. The source includes a photon source, and a scatter detector arranged between the object and the photon source. The photon source emits photons towards the scatter detector. The scatter detector scatters at least some of the photons and detects the scattered photons. The object scatters at least some of the photons that were first scattered by the scatter detector. The absorbing detector is arranged to detect scattered photons from the object. The image constructor constructs the three dimensional image based on the scattered photons.

Abstract: An imaging system includes a computed tomography (CT) acquisition unit and a processing unit. The CT acquisition unit includes an X-ray source and a CT detector configured to collect CT imaging data of an object to be imaged. The processing unit includes at least one processor operably coupled to the CT acquisition unit. The processing unit is configured to control the CT acquisition unit to collect at least one sample projection during rotation of the CT acquisition unit about the object to be imaged, compare an intensity of the at least one sample projection to an intensity of a reference projection, select a time to perform an imaging scan based on the comparison of the intensity of the at least one sample projection to the intensity of the reference projection, and control the CT acquisition unit to perform the imaging scan.

Abstract: An x-ray system comprising: at least one x-ray tube assembly; a collimator; an image detector; a monitor; means for determining the location of a Region of Interest (ROI) of a patient on said displayed image; a first controller; an image processing unit configured to modify the detected image for display on said monitor according to the image parts in said ROI; each x-ray tube assembly comprising a plurality of cathodes; and at least one anode; a second controller configured to control operating parameters of each one of said at least one x-ray tube assembly, said parameters comprising at least one collision location of electrons emitted from said plurality of cathodes on said at least one anode in reference to said collimator aperture; and means for controlling the directions of emitted x-ray beams.

Abstract: This invention is about a readout apparatus and method for time-of-flight and energy measurements with silicon photomultipliers (SIPM) coupled to a scintillator. The timing measurement can be as accurate as 50 ps or below, after calibration. The energy is measured using a time-over-threshold technique, and the energy resolution is only constrained by the scintillation statistics. In order to achieve low power of 10 mW per channel, a low impedance input amplifier and analog time-to-digital converters (TDCs) based on time interpolation are used. The readout circuit can be triggered by a single photoelectron (p.e.) with a signal-to-noise ratio (SNR) above 20 dB. The said readout circuit operates with SiPMs of different gain, polarity and matrix size. The preferred embodiment of the readout apparatus is a multi-channel application specific integrated circuit (ASIC) with 64 channels.

Abstract: Methods and apparatus for obtaining an image of light scattering biological tissue. A series of pulses of substantially monochromatic light of a first wavelength is generated and split into two parts, of which one part illuminates a scattering biological tissue at an intensity too low to damage the tissue, while a second part is upconverted to generate a pump beam. Sample light from the biological tissue, which may be scattered (or transmitted) light, or fluorescence, or Raman scattering, etc., is collected and directed from the scattering biological tissue, along with the pump beam, into a non-linear optical element, in a single pass or multiple passes. Parametrically amplified sample light emerging from the non-linear optical element is detected and analyzed or displayed.

Abstract: A radiation detection system includes a detector unit and at least one processor. The detector unit is configured to generate signals responsive to radiation events. The at least one processor receives the signals, and is configured to obtain a first count for at least one of the signals corresponding to a first energy window, the first energy window corresponding to values higher than a nominal peak value; obtain a second count for the at least one of the signals corresponding to a second energy window, the second energy window corresponding to values lower than the nominal peak value; obtain at least one auxiliary count for the at least one of the signals corresponding to at least one auxiliary energy window; and adjust a gain applied to the signals based on the first count, the second count, and the at least one auxiliary count.

Abstract: A radiation system includes a radiation source having an accelerator, the radiation source having a magnetic field associated therewith that is resulted from an operation of the accelerator, and a magnetic field source configured to provide a compensating magnetic field to at least partially counteract against the magnetic field that is resulted from the operation of the accelerator. A radiation system includes a radiation device having a radiation source, a patient support, and a protective guard located between the radiation source and the patient support, wherein the protective guard is moveably coupled to the radiation device or the patient support. A radiation system includes a particle generator for generating a particle, an accelerator for accelerating the particle, and a magnetic source for changing a trajectory of the particle, wherein the magnetic source comprises a permanent magnet.

Abstract: A detector arm assembly is provided that includes a stator, a detector head, a radial motion motor, and a detector head belt. The stator is configured to be fixedly coupled to a gantry having a bore. The detector head includes a carrier section that is slidably coupled to the stator and configured to be movable in a radial direction in the bore relative to the stator. The radial motion motor is operably coupled to at least one of the detector head or the stator. The detector head belt is operably coupled to the radial motion motor and the carrier section. Rotation of the radial motion motor causes movement of the detector head in the radial direction.

Abstract: An apparatus for analyzing a medical image includes an image receiving unit configured to receive two or more medical images from a medical device; a image registration unit configured to register the two or more received medical images; an overlapped area detecting unit configured to detect overlapped areas in the two or more registered medical images; and a lesion analyzing unit configured to analyze lesions in the two or more registered medical images by employing different analysis techniques in the detected overlapped areas.

Abstract: Methods for extracting a shape feature of an object and security inspection methods and apparatuses. Use is made of CT's capability of obtaining a 3D structure. The shape of an object in an inspected luggage is used as a feature of a suspicious object in combination with a material property of the object. For example, a false alarm rate in detection of suspicious explosives may be reduced.

Abstract: A method and a segmentation system are disclosed. An embodiment of the method includes providing an image representation of the structure; providing a start surface model, including a mesh with a plurality of vertices connected by edges; defining for each vertex a ray normal to the surface model at the position of the vertex; assigning more than two labels to each vertex, each label representing a candidate position of the vertex on the ray; providing a representation of likelihoods for each candidate position the likelihood referring to whether the candidate position corresponds to a surface point of the structure in the image representation; and defining a first order Markow Random Field with discrete multivariate random variables, the random variables including the labels of the candidate positions and the representation of likelihoods, finding an optimal segmentation of the structure by using an maximum a posteriori estimation in this Markow Random Field.

Abstract: A gantry system is provided. The gantry system may be used for acquiring image data and reconstructing the image data into output images. Image detectors include a detector arm and detector head. Image detectors are attached to a gantry in a compact configuration such that the image detector head may extend into the bore of a stator. The system can be a Nuclear Medicine (NM) imaging system to acquire Single Photon Emission Computed Tomography (SPECT) image information.

Abstract: Described here is a system and method for image reconstruction that can automatically and iteratively produce multiple images from one set of acquired data, in which each of these multiple images corresponds to a subset of the acquired data that is self-consistent, but inconsistent with other subsets of the acquired data. The image reconstruction includes iteratively minimizing the rank of an image matrix whose columns each correspond to a different image. The rank minimization is constrained subject to a consistency condition that enforces consistency between the forward projection of each column in the image matrix and a respective subset of the acquired data that contains data that is consistent with data in the subset, but inconsistent with data not in the subset.

Abstract: A mammograph is provided. The mammograph includes a source of X-rays; a detector of X-rays, the source being configured to emit at least one beam of X-rays to the detector; and an optic control device configured to control the direction of X-rays emitted by the source such that the X-rays emitted by the source are substantially parallel to one another.

Abstract: A collimator assembly is provided including a parallel-hole collimator and a pin-hole collimator. The parallel-hole collimator includes plural walls defining parallel holes therebetween, with the parallel holes arranged around a central opening. The pin-hole collimator includes a pin-hole formed in a body, with the pin-hole collimator disposed within the central opening.

Abstract: Described herein is a gamma camera imaging system in which a plurality of gamma cameras or multiheads are attached at a front face thereof to the outer surface of a flexible substrate. The flexible substrate is capable of forming an inner concave surface which in use is arranged to fit over or around a body part to be analyzed.

Abstract: The invention relates to an apparatus for generating an attenuation correction map. An image providing unit (5, 6) provides an image of an object comprising different element classes and a segmentation unit (11) applies a segmentation to the image for generating a segmented image comprising image regions corresponding to the element classes. The segmentation is based on at least one of a watershed segmentation and a body contour segmentation based on a contiguous skin and fat layers in the image. A feature determination unit (12) determines features of at least one of a) the image regions and b) boundaries between the image regions depending on image values of the image and an assigning unit (13) assigns attenuation values to the image regions based on the determined features for generating the attenuation correction map.